The present invention relates to recipe management systems for semiconductor fabrication processes, and more particularly to recipe management systems for comparing recipe versions for semiconductor processing tools utilized in the semiconductor fabrication process.
Recipe management systems are used in a semiconductor fabrication process to manage recipe correction and to prevent process engineers from running incorrect and non-approved recipes. A prior art recipe management system is described hereafter in connection with the fabrication system diagram of FIG. 1. The fabrication system 10 includes a database 12 connected to a Recipe Management System (RMS) server 14. The database includes a plurality of master recipe bodies for select tools used in the semiconductor process, including etch tools, deposition tools such as the Applied Material P5000 Mark II tool, and photolithography tools, such as a track tool 18. As should be known to those familiar with manufacturing integrated circuits, track tools have three main purposes in the process: (1) coating photoresist on a wafer; (2) baking the wafer; and (3) developing a circuit pattern on the wafer. Recipes for scanner and stepper photolithography tools are typically not stored in database 12.
RMS server 14 is shown connected to Industrial PC (IPC) 16. IPC 16 includes a computer integrated manufacturing (CIM) software package including a Tool Control System (TCS) for implementing task flow control for operating a tool such as track 18. Track 18 is shown as part of an inline tool physically combining at least two pieces of equipment, such as track 18 and stepper 20. IPC 16 communicates with track 18 using the Semiconductor Equipment Communications Standard (SECS) via low speed RS-232 serial lines. IPC 16 receives a recipe from the database 12 through RMS server 14. IPC 16 then uses the recipe to directly control the track 18 by issuing SECS commands. RMS server 14 is connected to database 12 and IPC 16 via an Ethernet connection.
A process recipe is sometimes modified by a process engineer at the IPC 16 for, for example, experimental test runs of processing tools. During actual process runs, however, it should be confirmed that the recipe that is being used by the IPC 16 to control the track tool 18 conforms to a master recipe in the database 12, which has been approved for use in a specific fabrication process. In order to accomplish this, the recipe currently resident at the IPC 16 is uploaded to the RMS server 14. The corresponding master recipe is also retrieved by the RMS sever 14 from the database 12. The bodies, i.e., the contents, of these recipes are then compared by the RMS server 14. If a match occurs, a message is sent to the IPC 16 indicating that the recipe is approved for use and the track tool is operated in the fabrication process. If a match does not occur, a mismatch message is sent to the IPC 16 indicating the need to retrieve an approved recipe from the database 12.
The RMS server 14 also handles recipe version management. A new version of a recipe stored in database 12 may be created at IPC 16, uploaded to RMS server 14 and stored as a new version of the corresponding recipe in database 12, thereby becoming an approved recipe.
Also shown in system 10 of FIG. 1 is Unix server 24. Unix server 24 includes a plurality of recipes for semiconductor exposure tools such as steppers and scanners. These recipes are also called job files. As one of ordinary skill will recognize, a stepper is an optical-based system that projects the pattern of a reticle onto a small area on the surface of the wafer. The projected image forms the processing pattern for one chip. The wafer is stepped in the X and Y directions to repeat the imaging for other chips. A scanner is also an exposure tool, only with a larger lens that the stepper.
Although shown connected to only one host 22, Unix server 24 is typically connected to a plurality of hosts. Each host 22 is connected to and associated with a single stepper 20 or scanner. Unix server 24 and host 22 are both industrial workstations, but the Unix server 24 stores master recipe files for steppers 20 and scanners, which are communicate with hosts 22. A typical recipe for a scanner or stepper will include X and Y coordinate information as well as other process parameters, such as light energy and focus information.
The host 22 provides a job file to the stepper 20 or scanner during a fabrication process for control of the stepper 20 or scanner. The host 22 and stepper 20 communicate through an Ethernet connection. Unix server 24 downloads an approved scanner or stepper recipe to host 22 for use in the process over a TCP/IP network using the File Transfer Protocol (FTP). Communications of job files between the Unix server 24 and host 22 are one way as indicated in FIG. 1. A process engineer can use host 22 to modify recipes if desired, such as for testing purposes.
Several problems exist with the system 10 of FIG. 1, particularly with respect to steppers 20 and scanners. The stepper and scanner tools typically become the bottle neck of the fabrication process when recipe file corruption occurs or mismatches occur between recipes in the Unix server 24 and the host 22. Despite this concern, the system 10 as shown in FIG. 1 does not have the ability to compare the recipe resident at host 22 and the recipe at Unix server 24 to determine whether a recipe file has been modified at the host 22. For one reason, recipe body communication between the Unix server 24 and the host 22 is not two way, i.e., the host software does not support exporting the recipe body back to the Unix server 24.
One solution available for ASML brand steppers and scanners available from ASML Co. of Tempe. Ariz. is a software utility installed on the host 22. The utility supports the SECS protocol and allows the Unix server. 24 to respond to a SECS command issued by the host 22. The host 22 issues a SECS command to the Unix sever 24 requesting modification time information for a selected recipe. The host 22 then compares the time information provided by the Unix server 24 for the recipe with the time information associated with the corresponding recipe resident at the host 22. If the time information does not match, the host 22 knows that it does not have the recipe that is resident at the Unix server 24, which must then be downloaded to the host 22. This add-on solution is not very attractive for several reasons. First, the software utility is very expensive, as much as $6,700 per host installation. Second, RS232 serial interface hardware must be added to and between host 22 and server 24. Further, the solution only compares modification times associated with a reipe and not recipe bodies or contents. The solution, therefore, lacks the ability to identify for a process engineer the specific changes that have been made to the recipe.
Therefore, there remains a need for a new, cost effective and robust method of ensuring that recipes being processed by scanners and steppers conform to released master recipes. To that end, there remains a need for a new method and system for comparing recipes for scanner and stepper tools utilized in the semiconductor manufacturing process.
A recipe management system is provided including a processor configured to receive a first job file for a processing tool through a network, said first job file including a master job file for said processing tool. The processor also receives a second job file through the network from a host processor associated with the processing tool. The processor compares the first and second job files, wherein the processor determines whether the first and second job files differ.
A semiconductor manufacturing method is also provided. A first job file including a master job file for a processing tool is received through a network. A second job file is also received through the network from a host processor associated with the processing tool The job files are then compared to determine whether the first and second job files differ.
The system and method described above provide a cost effective means of comparing job files, particularly for exposure tools, to ensure that only approved job files are used in the fabrication process. File transfer is accomplished via network communications rather than using lower speed SECS RS-232 serial communications. When comparing exposure unit job files, no separate database of master job files is needed as with comparing track tools in prior art system 10, because the exposure unit job files are already resident at the master job file processor. Further, exposure unit login information can be collected and used for maintenance purposes. Still further, expensive software and hardware solutions are avoided because application tools available with standard operating systems may be utilized to facilitate file transfer. Also, when upgrading a prior art system 10, modifications need only be made to the IPC 16, rather than each host processor 22.